When looking at the components of the chimney, we need to look that everything fits and sits well. One area that installers forget to check sometimes is where the spark arrestor meets the metal chimney cap. Gaps here can lead to moisture problems in the home.

When we see rust signs on the metal chimney cap, we know that water is standing there for a while. These caps are meant to shed water away. If rusting enough, combined with the standing water, we know that we can have a leak.

Spark arrestors can sit out in the open, or they can have a cover over them. Our first concern should be is there an opening that can allow an animal into the flue. On both of these units, we see black soot signs, indicating cleaning is needed. A word about spark arrestors: these stop sparks from the fire from landing on the roof. Different parts of the country have different rules about how large the opening can be.

Before we had metal flues and metal chimney caps, we used cement caps on the chimneys. Like the metal cap, the purpose is to shed water away from the chimney flue. In this case, we see that the cap is cracked and deteriorating, so it needs to be repaired.

The condition of the brick needs to be checked. Older fireplaces from the 1920s may only have the brick. Fireplaces from the 1980s may have a clay flue liner in them. In either case, damage to the chimney can mean damage within the flue. On the left, we see gaps occurring in the mortar. On the right, we see the chimney separating.

This normally falls in the Roof Covering section, but I am mentioning it here again. Roof penetrations, like the chimney, should be properly sealed to prevent leaks. This chimney appears to have had leaks in the past, and probably will again. There is extra sealant around the chimney flashing, and the flashing has a gap again. Rain hitting the chimney will flow down the sides of the bricks into the home.

This chimney does not have the spark arrestor, which allows us to see the clay liner for the flue. That is the terracotta colored square in the middle of the cement cap.

This type of vent is used in place of a chimney. This unit was not near to any windows, which can be a problem. I have also seen them under covered patios, where creosote can collect on the ceiling. My only issue with this one is that the metal parts of the vent can become quite hot when the fireplace is in use. Some units will have a mesh cage over this vent to prevent someone from accidentally bumping into it.

Here is another picture of a fireplace vent.

This may not look like the metal fireplace vent, but this is the vent for an older style heater. This vent situation applies to many furnace vents, like for the water heater. As the vent travels through the home, the vent duct has to be protected from coming into contact with the metal surfaces. In this home, the vent was supported by strapping it into the framing; however, this strapping places the duct into contact with the wood. When this vent heats, we have the potential for a fire. The vent should be a couple of inches away to be safe.

This may or may not be a problem over time. This house has a steeply angled roof over the front portion with a lower roof in the back, which is not at a great pitch. Where the two roof planes meet, the chimney rises through the structure. The concern is that during heavy rains, there may be a good deal of water coming through this area (particularly the left side of the picture). Heavy water passage here may penetrate into the trim of the chimney. The cricket is the bump out which diverts water to the sides of the chimney. The cricket is also called the saddle. However, there may be enough space for water to pass where the trim may not be effected. The flashing around the chimney was properly installed.

This home was advertised as having fireplaces. Not quite right. These are only the chimney portion. This would cause a problem with energy efficiency and possibly rodents. The conditioned space s open to the unconditoned space of the attic. You would be attempting to cool or heat the attic with this setup

I should not have been able to take this picture. I am standing on the roof, looking down the flue. The black material on the bricks is creosote, which is flammable. There happens to be no damper on this chimney, so with no cap on the top, we have the equivalent of an open window all year long, not energy efficient. Next, the cap over the top of the flue helps prevent rain from coming into the flue, so we can have moisture problems. Finally, we will want a spark arrestor to prevent any sparks from landing on the roof.

One place to see foundation movement in older homes is in the flue. Here we can see that the chimney has shifted a few times leaving the bricks not quite aligned anymore. What we may not notice from looking down the flue, but what we will see in the attic, is that there are now gaps in the flue, so fumes will not be vented to the exterior.

Going into the attic to check out the chimney is important. This was a strange case. Where I expected to find the chimney, I found these stacked bricks. I thought that maybe the bricks with mortar for the flue were behind these stacked bricks, which might have been left over from the chimney build. I was wrong. I found that I could access the interior of the flue by removing some of these loose bricks.

Metal flues are more the standard for new construction. I find that the blown insulation often is blown all over without thought. This flue was not so bad (they can be covered in insulation), but we do not want insulation touching the flue, since this is a fire hazard. What made this picture a choice for me was that there was more than insulation touching the flue; we have packing material too. I have found plastic bottles and other debris being left near flues in the attic.

We have to be careful with other flammable objects touching the flue, but we also need them to be away from the flue. This metal flue was hard to reach, so maybe this is why no one caught this problem previously. The framing for the roof comes within an inch of the flue. This is too close, so this situation is considered a potential fire hazard.

Moving into the living space, we need to be concerned about flammable surfaces around the fireplace. In this picture, we see that the builder placed tile around the fireplace opening for fire safety. There was also tile on the floor for the hearth for the same reason. Not often, but there are times when I find that this has been forgotten. I also check the gas supply valve to see how it operates.

Since this fireplace has never been used, I was able to take a clear photograph of the damper. With creosote build-up, this is sally hard to see. The damper is a door closing off the fireplace from the flue. When the fireplace is in use, the damper should open fully. When not in use, the damper should close fully. If the damper is left open, you can think of it like leaving a window open, which is energy inefficient. If you do find this area and the flue to be covered in soot, you need to have them cleaned. The soot is creosote, which is a flammable material.

Are you curious about the home that you own? Looking to save money around the home? Maybe you are curious about green homes. That is why I became a home inspector. I love working on my own home. I want to share my discoveries with you, so there is something here for you in this blog. I am a professional home inspector in Houston who is here to help you to have a better life in your home. Thanks!